The Arab League expressed "growing concern" over the developments in Syria
and called on the authorities to immediately stop acts of violence against protesters, Qatar's state news agency QNA reported on Sunday.

Arab League Secretary-General Nabil Elaraby issued a statement expressing "growing concern and strong distress over the deteriorating security conditions in Syria due to escalating violence and military operations in Hama and Deir ez-Zor, as well as other areas of Syria", QNA said.

Meanwhile, at least 57 civilians were killed in Syria on Sunday, according to human rights activists in the country.

Syrian President Bashar Assad
has defended his crackdown on "outlaws" despite rising international condemnation, saying that Damascus had "an obligation" to punish those who are "terrorizing the population."

"These are preliminary figures. The numbers of casualties are escalating by the hour," Suhair al-Atassi, an activist with the Syrian Revolution Coordinating Union, said.

Rights groups say Syrian security forces have killed at least 1,600 civilians since protests calling for an end Assad's 11-year rule began in March.

Syrian authorities have expelled most independent journalists, making it difficult to verify the death toll and reports of the fighting.